Fibrinase

Synopsis

Fibrinase (Nattokinase / Soybean Fibrinase): A Comprehensive Reference

Terminological Note and Scope

The common name fibrinase has been applied, across different scientific and commercial contexts, to more than one enzyme. In classical coagulation biochemistry, the term "fibrinase" has historically been used as a synonym for Factor XIII (coagulation factor XIII; also known as fibrin-stabilizing factor, fibrinoligase, and plasma transglutaminase) — an endogenous human plasma protein that stabilizes fibrin clots rather than dissolving them. However, in the contemporary dietary supplement and nutraceutical field, the trade and label designation Soybean Fibrinase refers exclusively to nattokinase (NK), a fibrinolytic serine protease derived from fermented soybeans. These are biochemically distinct entities with opposite effects on the fibrin network. This article addresses both identities, with primary depth devoted to the nattokinase interpretation, which is the commercially marketed dietary supplement form. A section on the endogenous Factor XIII use of the term is also included for completeness.

Part I: Fibrinase as Soybean Fibrinase (Nattokinase)

1. Identity: Names, Chemical Characteristics, and Natural Source

Nattokinase (NK) is not related to any of the known kinases. NK is a serine protease purified and extracted from natto, a traditional Japanese food produced from the fermentation of soybeans with the bacterium Bacillus subtilis (natto). In supplement labeling, nattokinase is frequently listed under the trade designation "Soybean Fibrinase" or "Soybean Fibrinase Extract," reflecting both its origin (soybean fermentation) and its primary pharmacological function (fibrinolysis — the enzymatic dissolution of fibrin).

Nattokinase is an enzyme produced by B. subtilis var. natto, discovered by Sumi et al. in 1987. The molecular weight of nattokinase is approximately 27.7 kDa; it consists of 275 amino acid residues. Contrary to its name, nattokinase is a subtilisin family serine protease and has no kinase activity.

Nattokinase is a kind of alkaline serine protease with strong fibrinolytic and thrombolytic activity, which is secreted by Bacillus natto and discovered in natto by Sumi et al. Its enzyme activity is commercially measured and expressed in Fibrinolytic Units (FU), a standardized unit reflecting the rate of fibrin degradation.

Its systematic enzyme classification places it within Subtilisin family serine endopeptidases (EC 3.4.21.x), belonging to the broader chymotrypsin/subtilisin clan of serine proteases. As a serine protease produced by Bacillus subtilis, nattokinase has potential anti-coagulatory, thrombolytic, anti-atherosclerotic, lipid-lowering, and anti-hypertensive effects.

2. Traditional and Historical Use

Natto, a fermented soybean product, has been consumed as a traditional food in Japan for thousands of years. Nattokinase, a potent blood-clot dissolving protein, is produced by the bacterium Bacillus subtilis during the fermentation of soybeans to produce natto. The food itself — rather than any isolated extract — is what has been historically consumed.

Natto, a cheese-like food made of soybeans fermented with Bacillus subtilis, has been consumed as a traditional food in Asian countries for more than 2,000 years. Natto consumption is believed to be a significant contributor to the longevity of the Japanese population. Intake of natto and other related fermented soy products is inversely related to the incidence of cardiovascular diseases; hence, long-term consumption of natto is considered to be one of the important reasons for the longevity of the Japanese.

The consumption of nattō is linked to many beneficial health effects, including the prevention of high blood pressure, osteoporosis, and cardiovascular-associated disease. Traditionally, natto was prepared by wrapping boiled soybeans in rice straw (which naturally harbors Bacillus subtilis) and allowing fermentation at warm temperatures over one to two days. The resulting food is characterized by a distinctive pungent odor, sticky texture produced by poly-gamma-glutamic acid (PGA), and strong umami flavor.

Before 1987, very little was known about the scientific basis for the use of this alternative remedy in improving overall cardiovascular health. Natto was consumed empirically as a health-promoting food, particularly in eastern Japan, based on centuries of dietary tradition, without scientific understanding of the active enzymatic component responsible for its cardiovascular effects.

3. Scientific Discovery

In 1980, Hiroyuki Sumi, a Japanese researcher at the Chicago University Medical School, discovered that natto can dissolve artificial fibrin. Sumi and his team extracted an enzyme from natto that not only degraded fibrin but also a plasmin substrate. He named this novel, fibrinolytic enzyme "nattokinase."

In 1987, researcher Dr. Hiroyuki Sumi placed a sample of natto on an artificial blood clot in a petri dish and watched it dissolve the clot within 18 hours. That discovery launched decades of research into the enzyme as a natural fibrinolytic agent.

In 1987, Sumi et al. extracted nattokinase from natto with saline and reported that this alkaline protease was responsible for strong fibrinolytic/antithrombotic activity of natto. NK has been extensively studied in Japan, Korea, and China. Recently, the fibrinolytic (anti-clotting) capacity of NK has been recognized by Western medicine.

4. Natural Source and Other Microbial Hosts

The enzyme is produced by the bacterium Bacillus subtilis var. natto during fermentation. Importantly, it is the bacteria, not the soybean, that creates the enzyme. This is why it can be produced using alternative substrates like chickpeas without any change in activity. Except in fermented soybean, nattokinase is also found in bacillus, actinomyces, epiphyte, and alga.

B. subtilis natto produces several molecules associated with human health, including large amounts of vitamin K2 (menaquinone-7), important for bone robustness; pyrroloquinoline quinone (PQQ), a natural antioxidant with energizing and anti-fatigue effects; and nattokinase. This means that whole natto food also delivers vitamin K2 alongside nattokinase, a distinction significant for interactions with vitamin K-sensitive medications, though purified supplement extracts typically remove vitamin K2 during processing.

5. Common Supplement Forms and Preparations

Commercially available nattokinase supplements — frequently labeled as Soybean Fibrinase — are produced by industrial fermentation of Bacillus subtilis var. natto with soybeans or alternative substrates, followed by extraction and purification of the enzyme. The purified enzyme is dried and formulated into various delivery forms:

Standard capsules and tablets: The most common form. Potency is measured in Fibrinolytic Units (FU) per capsule. Product labels commonly state nattokinase (Soybean Fibrinase) at 150 mg supplying 3,000 FU (Fibrinolytic Units).
Enteric-coated capsules: Enteric-coated capsules protect the enzymes from stomach acid, ensuring they reach the small intestine where absorption is more favorable. This formulation is widely used to maximize bioavailability of the active enzyme.
Combination formulas: Nattokinase is often combined with other fibrinolytic or proteolytic enzymes, such as serrapeptase or lumbrokinase, in multi-enzyme preparations marketed for cardiovascular or circulatory support.
Liposomal preparations: Some manufacturers offer nattokinase encapsulated in phospholipid liposomes, purporting to enhance absorption, though controlled comparative bioavailability data in humans are limited.

The standard potency unit is the Fibrinolytic Unit (FU), which quantifies fibrinolytic activity in standardized assay conditions. Dosages in research studies and commercial products range from 2,000 FU to 10,800 FU per day.

6. Key Constituents and Active Compounds

The pharmacologically active component in soybean fibrinase supplements is the nattokinase enzyme itself. The enzyme belongs to the subtilisin superfamily of serine proteases and carries no intrinsic kinase activity despite its name. Additional co-occurring bioactive molecules present in whole natto food include vitamin K2 (menaquinone-7) and poly-gamma-glutamic acid; however, these are generally absent from purified nattokinase supplements.

7. Established Mechanisms of Action

Nattokinase acts through multiple, synergistic pathways on the fibrinolytic and coagulation systems:

7.1 Direct Fibrin Degradation

Nattokinase has a stronger fibrinolytic activity than plasmin in vivo, and can even hydrolyze fibrin directly. On the one hand, it can directly hydrolyze fibrin clots, activate plasminogen to convert into plasmin, and degrade fibrinogen and fibrin to dissolve thrombus.

7.2 Upregulation of Tissue Plasminogen Activator (t-PA) and PAI-1 Inhibition

NK can break down blood clots by directly hydrolyzing fibrin and plasmin substrate, converts endogenous prourokinase to urokinase (uPA), degrades PAI-1 (plasminogen activator inhibitor-1), and increases tissue plasminogen activator (t-PA) which supports fibrinolytic activity.

It is now known that NK not only degrades fibrin directly and effectively but also increases the release of tPA with a subsequent increase in the formation of plasmin. Plasminogen activator inhibitor 1 (PAI-1) is the primary inhibitor of tPA and regulates fibrinolytic activity in the fibrinolytic cascade. In a study investigating the mechanism by which NK exerted its fibrinolytic effect, NK enhanced fibrinolysis through cleavage and inactivation of PAI-1. In this study, NK was shown to cleave active recombinant prokaryotic PAI-1 into low-molecular-weight fragments as well as enhance tissue-type plasminogen activator–induced fibrin clot lysis.

On the other hand, it can enhance the activity of the endogenous fibrinolytic system by activating tissue plasminogen activator (t-PA), while inhibiting plasminogen activator inhibitor-1 (PAI-1) to reduce fibrinolysis inhibition and improve the efficiency of thrombolysis through a dual mechanism.

7.3 Reduction of Coagulation Factors

NK inhibits thrombosis through multiple pathways including directly degrading fibrin and plasmin substrate, degrading PAI-1 and increasing the level of t-PA, suppressing platelet aggregation, reducing the level of fibrinogen, factor VII and VIII to inhibit coagulation, as well as degrading Toll-like receptor 4 (TLR4) receptor to alleviate inflammation.

In a human trial, three groups (healthy volunteers, patients with cardiovascular risk factors, and patients undergoing dialysis) were orally administered two capsules of NK (2,000 FU/capsule) on a daily basis. After two months, a significant and similar decrease in factor VII, factor VIII, and fibrinogen was observed in all of the groups. No adverse effects were detected during the two-month trial and heart rate, body weight, and uric acid levels remained stable.

7.4 Antihypertensive Mechanisms

It was already known that nattokinase had high gastrointestinal stability, and it might reduce blood pressure by cleaving plasma fibrinogen after absorption in the small intestine. More significantly, degradation products of nattokinase were demonstrated to exert different antihypertensive effects — inhibition of angiotensin I converting enzyme and plasma angiotensin II level.

NK-01 (a nattokinase-like protease) could inhibit the activity of coagulation factors through the up-regulation of proteinase C inhibitors and protein S. NK-01 also could inhibit the angiotensinogen conversion to AngII and promote the degradation of kininogen to reduce the blood pressure.

7.5 Antiplatelet Activity

Nattokinase also enhanced the production of clot-dissolving agents such as urokinase through the conversion of prourokinase to urokinase. Furthermore, NK was shown to be capable of blocking thromboxane B2 formation from collagen-activated platelets, displaying excellent antiplatelet aggregation and antithrombotic activities in vitro and in vivo.

7.6 Oral Bioavailability

Both NK and lumbrokinase (derived from earthworms), unlike most proteins, are more resistant to the highly acidic gastric fluids in the stomach and can be absorbed in the later sections of the digestive tract. In 1995, Fujita and colleagues demonstrated that NK could be absorbed from the rat intestinal tract in an intact form and degraded fibrinogen in plasma blood samples. Subsequently, in 2013, a research team in the United States detected intact NK in the serum of healthy humans after they were administered a single, oral dose of NK (2,000 FU/100 mg) in a capsule. Other studies have also shown that oral administration of NK can enhance fibrinolytic activity in plasma.

Some studies have pointed out that its structural stability is strong, and it may resist the degradation of gastrointestinal proteases in a complete molecular form to achieve absorption. After absorption, it enters the liver through the portal vein system, enters the systemic circulation after initial metabolism, and distributes to target tissues such as blood vessels.

8. Scientific Evidence by Area of Use

8.1 Cardiovascular Disease and Thrombosis — Overview of the Evidence Base

In addition to these favorable cardiovascular profiles, nattokinase can be orally administered with inexpensive cost, proven safety, and preventative efficacy. NK has been extensively studied in Japan, Korea, and China. Recently, the fibrinolytic (anti-clotting) capacity of NK has been recognized by Western medicine.

8.2 Hypertension (Blood Pressure Reduction)

The strongest and most consistent clinical evidence for nattokinase supplementation pertains to blood pressure reduction. As a fibrinolytic enzyme from fermented soybean, nattokinase has been shown to be potentially beneficial for cardiovascular health.

A 2023 systematic review and meta-analysis of RCTs constitutes the highest-quality clinical synthesis available: Six studies were eligible for quantitative analysis with 546 participants. The overall methodological quality of included studies was high. Nattokinase supplementation significantly reduced systolic blood pressure (MD = −3.45, 95% CI: −4.37 to −2.18, p < 0.00001) and diastolic blood pressure (MD = −2.32, 95% CI: −2.72 to −1.92, p < 0.00001) as compared to placebo.

This study further supports that nattokinase can be used as an effective adjunctive therapy for hypertension, but relatively low-dose supplementation of nattokinase may have no significant lipid-lowering effect. More work will need to be done to determine whether the positive efficacy of nattokinase on cardiovascular risk factors is dose-dependent.

Evidence strength for blood pressure: Moderate to good — consistent effect across multiple RCTs with high methodological quality; the magnitude of reduction is statistically significant and clinically meaningful, though modest in absolute terms.

8.3 Atherosclerosis and Lipid Profile

A large retrospective clinical study evaluated nattokinase at 10,800 FU/day: In this clinical study involving 1,062 participants, the objective was to examine the efficacy of NK in atherosclerosis and hyperlipidemia and safety at the dose of 10,800 FU/day after 12 months of oral administration. The investigators found that NK at a dose of 10,800 FU/day effectively managed the progression of atherosclerosis and hyperlipidemia with a significant improvement in the lipid profile.

These findings provide clinical evidence on the effective dose of NK in the management of cardiovascular disease and challenge the recommended dose of 2,000 FU per day.

However, the 2023 meta-analysis found more nuanced lipid results: Relatively low total dosage of nattokinase had a negative effect on blood total cholesterol (MD = 5.27, 95% CI: 3.74 to 6.81, p < 0.00001), high-density lipoprotein cholesterol (MD = −2.76, 95% CI: −3.88 to −1.64, p < 0.00001), and low-density lipoprotein cholesterol (MD = 6.49, 95% CI: 0.83 to 12.15, p = 0.02). No significant correlation was found between nattokinase supplementation and triglyceride (p = 0.71).

The direction and magnitude of cholesterol effects in this meta-analysis were variable and complex, suggesting that lower doses may in fact unfavorably affect lipid markers, while high-dose, long-term administration may be necessary for beneficial lipid effects. Evidence strength for lipid effects: Preliminary and inconsistent — dose-dependency is suspected but not established; the relationship between dosage, treatment duration, and lipid outcomes requires further investigation in adequately powered, well-controlled trials.

8.4 Coagulation Factor Reduction and von Willebrand Factor

It was confirmed that oral administration of nattokinase (or natto) produced a mild and frequent enhancement of the fibrinolytic activity in the plasma as indicated by the fibrinolytic parameters and the production of tissue plasminogen activator. A multicenter North American RCT found that nattokinase consumption was associated with reduced blood pressure and reduced von Willebrand factor, a recognized cardiovascular risk marker.

Elevated levels of factor VII and VIII are associated with greater risk of cardiovascular disease due to the potential of these factors to trigger a blood coagulation cascade. In a human trial, three groups (healthy volunteers, patients with cardiovascular risk factors, and patients undergoing dialysis) were orally administered two capsules of NK (2,000 FU/capsule) on a daily basis. After two months, FDP fragments and d-dimers were observed four and six hours after NK administration, respectively, and factor VIII activity declined four hours after NK ingestion. The results of this study indicated that multiple different pathways may be involved in NK fibrinolysis and anti-coagulation activity.

Evidence strength: Preliminary — based on small, short-term human studies and mechanistic data. Larger controlled studies needed.

8.5 Vascular Disease and Venous Thrombosis

In a real-world data study, patients with deep vein thrombosis were treated with fondaparinux (7.5 mg/day subcutaneous) for 30 days and then nattokinase (tablet, 100 mg/2,000 FU/daily per oral administration for 30 days). This observational study reported the safety of nattokinase in patients with vascular diseases. The study design (real-world observational) limits causal inference.

8.6 Amyloid and Neurodegenerative Disease (Exploratory)

Preclinical and early research has examined nattokinase for applications beyond cardiovascular disease. The field of investigation relates generally to degradation and clearance of amyloid, prion and other protein aggregates, and more specifically to methods for degrading and reducing amyloid fibril formation in therapeutic intervention in treating Alzheimer's disease, prion diseases, and other amyloidoses. Although much research has been carried out on nattokinase, there has been no interest in whether it can degrade amyloids, which are also highly insoluble and protease resistant. This area remains at the patent/preclinical stage with no human clinical trial data published at the time of this writing.

Evidence strength: Very preliminary — in vitro and patent-stage only; no clinical data available.

9. Body Systems and Health Areas

Cardiovascular system: Primary research focus. Evidence supports antithrombotic, fibrinolytic, and antihypertensive effects. The effects of NK include antihypertensive, anti-atherosclerotic, lipid lowering, anti-platelet, and neuroprotective effects.
Hemostatic system: Direct effects on fibrin, fibrinogen, PAI-1, coagulation factors VII and VIII, and von Willebrand factor, all documented in human studies.
Vascular endothelium: Enhancement of t-PA release from endothelial cells; modulation of vascular tone through ACE inhibition mechanisms.
Renin-angiotensin system: Degradation products of nattokinase demonstrated to inhibit angiotensin-converting enzyme (ACE) activity and reduce angiotensin II levels, contributing to blood pressure reduction.
Platelet function: In vitro and animal data showing inhibition of platelet aggregation and thromboxane B2 formation.
Neurological (exploratory): Preclinical investigation into amyloid fibril degradation. No clinical translation to date.

10. Dosage Forms and Doses Reported in Studies

Dosing in nattokinase research is expressed in Fibrinolytic Units (FU), a standardized measure of enzymatic activity. The following represent doses specifically documented in cited studies:

In a human trial, three groups were orally administered two capsules of NK (2,000 FU/capsule) on a daily basis for two months.
In a clinical study involving 1,062 participants, the dose of NK used was 10,800 FU/day after 12 months of oral administration. Each tablet contained 3,600 FU.
In one unpublished study, 12 patients hospitalized for ischemic stroke who were receiving heparin and low-dose aspirin or clopidogrel also received nattokinase 6,000 FU/day for 7 days.
In another protocol, nattokinase was administered as a tablet, 100 mg/2,000 FU daily per oral administration for 30 days.
A common commercial formulation provides nattokinase (Soybean Fibrinase) 150 mg supplying 3,000 FU (Fibrinolytic Units) per serving.

Findings from the 1,062-participant study provide clinical evidence on the effective dose of NK in the management of cardiovascular disease and challenge the recommended dose of 2,000 FU per day.

11. Safety Considerations and Drug Interactions

11.1 General Safety in Clinical Trials

No notable adverse events were reported in all studies due to intake of nattokinase in the 2023 systematic review and meta-analysis of RCTs (546 participants across six studies). When taken alone at studied doses (up to 10,800 FU/day), nattokinase has a strong safety profile with no serious bleeding events in clinical trials involving over 1,000 participants.

11.2 Interaction with Anticoagulants and Antiplatelet Agents

Nattokinase carries meaningful interaction risks with anticoagulants and antiplatelet agents. Nattokinase has pharmacologic effects that could increase the risk of bleeding when administered with anticoagulant and antiplatelet agents.

Anticoagulant/antiplatelet/fibrinolytic drugs: Theoretically, nattokinase may increase the risk of bleeding. In a small study of healthy young men, enhanced fibrinolysis and antithrombosis after a single-dose of oral nattokinase occurred, although effects in this group were deemed to be within normal range.

Lab studies indicate nattokinase is a heparin-binding protein with a binding affinity of approximately 250 nM, and the interaction is chain-length dependent. It also interfered in heparin interactions with antithrombin and fibroblast growth factors.

The antithrombotic, fibrinolytic, and antiplatelet activities observed with nattokinase in vitro and in animal studies raise concerns that nattokinase may increase the risk of bleeding when administered with anticoagulant and antiplatelet agents. In one unpublished study, 12 patients hospitalized for ischemic stroke receiving heparin and low-dose aspirin or clopidogrel also received nattokinase 6,000 FU/day for 7 days. Coadministration of nattokinase reportedly increased bleeding time and clotting time and decreased prothrombin time, thromboplastin time, and D-dimer levels.

11.3 Interaction with Warfarin and Vitamin K

High concentrations of vitamin K2 in natto (a traditional Japanese food) can reduce the international normalized ratio (INR) when coadministered with warfarin; this may also occur with nattokinase supplements if vitamin K2 is not removed during the production process. Most commercial purified nattokinase supplements process out vitamin K2, but this should be verified on a product-by-product basis.

11.4 Case Reports of Adverse Events

Patients with mechanical heart valves require consistent anticoagulation with warfarin to prevent thrombosis. Nattokinase cannot substitute for warfarin in this setting, as demonstrated by the case of valve thrombosis when a patient made this substitution independently (Elahi et al., 2015).

There is a theoretical risk of bleeding, based on a case report of acute cerebellar hemorrhage in a patient with a history of ischemic stroke.

11.5 Other Drug Interactions

Nattokinase has additional clinically significant interactions beyond anticoagulants and antiplatelets, most notably with NSAIDs, acetaminophen, and potentially with medications affecting P-glycoprotein pathways, all of which can compound bleeding risk through multiple mechanisms.

11.6 Contraindicated or Cautioned Populations

Patients with active bleeding or recent hemorrhagic stroke should avoid nattokinase. The fibrinolytic effects could worsen ongoing bleeding or promote rebleeding at fragile sites. Those with bleeding disorders or significant thrombocytopenia face similar contraindications.
Pregnant women lack safety data for nattokinase. Given the absence of teratogenicity or obstetric outcome studies, avoidance during pregnancy is prudent.
Patients with severe hepatic impairment may have impaired coagulation factor synthesis, creating heightened bleeding risk with fibrinolytic agents.
Information regarding safety and efficacy in pregnancy and lactation is lacking.

11.7 Allergy Considerations

Natto allergy is an immediate allergy mediated by IgE and shows positive results in the skin prick test (SPT), ELISA, and basophil activation test for natto. Nattokinase has been identified as a potential allergen (designated Bac s 1) from this source. Individuals with known soy or natto hypersensitivity should exercise caution with nattokinase supplements.

11.8 Evidence Gaps in Safety Research

Clinical guidance emerging from the literature is consistent: avoid combining nattokinase with anticoagulant or antiplatelet therapy without explicit clinician oversight, do not substitute it for prescribed anticoagulants, stop it before surgery, and monitor for bleeding if co-use is unavoidable; however, quantifying absolute risk or safe dosing in co-medicated patients is not settled due to limited randomized data and variable product quality. The evidence base needs controlled trials that measure bleeding endpoints, interaction pharmacodynamics, and standardized product formulations before more definitive recommendations can be made.

Part II: Fibrinase as Endogenous Factor XIII (Classical Biochemical Usage)

Identity and Biochemistry

In classical coagulation biochemistry, "fibrinase" was an early synonym for coagulation Factor XIII (FXIII). Factor XIII (also known as fibrin stabilizing factor, fibrinoligase, or plasma transglutaminase) is a plasma glycoprotein that circulates in blood as a zymogen (Mr ≈ 320 kD) complexed with fibrinogen.

The Nature journal recorded the historical biochemical definition of this term: The primary action of fibrinase is, in the presence of calcium, to convert a urea-soluble fibrin (fibrin s) to a urea-insoluble gel (fibrin i). It was during the course of an investigation commenced to further the characterization of the tissue inhibitor that a number of observations were made which led to a reconsideration of the enzyme fibrinase. This enzyme occurs in blood and has been identified with the 'Laki–Lorand factor' and 'fibrin-stabilizing factor' by Loewy et al., who investigated a number of its properties.

This fibrin-stabilizing factor (XIII) was discovered in 1944, and its role was confirmed in 1966. It plays a crucial role in stabilizing the fibrin clot during the final stage of clotting.

Critically, the action of endogenous Factor XIII is opposite to that of nattokinase: Factor XIII, also referred to as fibrin stabilizing factor, plays a crucial role in the coagulation cascade by enhancing the stability of blood clot formation. The plasma form of Factor XIII is a protein heterodimer composed of A and B subunits expressed by bone marrow and mesenchymal lineage cells. Factor XIII functions as a transglutaminase, catalyzing peptide reactions responsible for cross-linking fibrin mesh.

Factor XIIIa causes crosslinking of the fibrin polymers, making the fibrin clot mechanically more stable, less deformable and more resistant to dissolution by plasmin. Factor XIII (classical fibrinase) is therefore a pro-coagulant, clot-stabilizing enzyme — not a fibrinolytic agent. It is not sold as a dietary supplement for fibrinolytic purposes and should not be confused with the soybean fibrinase (nattokinase) described in Part I.

Summary of Evidence Quality

Blood pressure reduction: Supported by multiple RCTs and a 2023 systematic review/meta-analysis; evidence quality is moderate-to-good.
Anti-thrombotic / fibrinolytic activity: Well-established in animal and in vitro models; supported in small human trials for coagulation factor changes; considered preliminary for clinical thrombus endpoints in humans.
Lipid/cholesterol effects: Inconsistent across studies; likely dose-dependent; evidence is currently insufficient and conflicting.
Atherosclerosis management: Supported by one large retrospective study (1,062 participants) at a high dose (10,800 FU/day); requires replication in prospective RCTs.
Neurodegenerative / amyloid applications: Entirely preclinical and speculative; no human trials.
Safety in isolation: No serious adverse events in RCTs up to 10,800 FU/day; interactions with anticoagulants and antiplatelet drugs represent a clinically significant, mechanistically founded concern that lacks large controlled interaction studies.